Turf grasses are widely used in recreational areas, parks, golf courses, bowling greens, athletic fields and domestic lawns. There is a demand for turf to have a uniform green colour so as to provide a pleasing appearance. This is particularly so for televised sporting events where it is desirable that a playing field have a healthy looking and uniform green colour. However, under adverse conditions such as drought and frosts, grass can lose its natural colour and in some circumstances change to an undesirable appearance. Turf colorants that can impart a green colour to discoloured turf have been developed with a view to artificially returning a playing field to a desirable colour or to simply make the turf appear more robust and healthy. Green colorants are also used to colour sand and in particular, divot sand as used on golf courses.
A green colorant that is widely used commercially is a pigment based colorant comprising a water insoluble pigment suspended in an aqueous solution. In practice, application problems may be experienced when applying pigment based colorants. Such problems include blockage of application nozzles and equipment cleaning difficulties.
Other colorants for use in the agricultural industry are also available. Such colorants are based on water soluble dyes. As the dyes are water soluble, the above-mentioned application difficulties associated with pigment based colorants are generally not experienced. The dye based colorants typically contain blue or red dyes and are used as markers for spraying herbicides, insecticides and the like. Blue colorants are also used to impart a blue colour to water features. The blue dyes may also be used on turf but impart a blue colour, which is generally not considered desirable.
However, there are some concerns regarding repeated use of pigments on playing fields and the like for a number of reasons. First, there are potential toxicity problems to those spraying the dyes and those playing on, or otherwise using the field. Although pigments commonly used to colour turf are considered safe to human health, there are few, if any, studies on long term exposure of these chemicals. Still further, there may be potential environmental hazards associated with build up of these chemicals in the environment as a result of repeated spraying. Generally a respray is necessary whenever the grass is cut. In some cases, a playing field may be sprayed at weekly or fortnightly intervals immediately prior a match or game being played on the field.
It is therefore an object of the present invention to provide an alternative colorant composition that is suitable for use on turf or other suitable surfaces.